The present invention relates to an ignition system of capacitor discharge type for the internal combustion engine in which the time of spark discharge is lengthened.
In order to prevent the after-glow or smolder of ignition plugs and to improve the ignition performance thereof, a rapid rise of the spark discharge current and a long discharge time are required. Various combinations of the ignition circuits of capacitor discharge type and current interruption type have conventionally been suggested in an attempt to meet these two requirements. (See U.S. Pat. No. 3,280,809)
The conventional ignition systems of these types, however, require a specific inherent DC-DC converter as an ignition system of the capacitive discharge type, for charging a capacitor at high voltage on the one hand and an ignition coil of a large size to store magnetic energy for interrupting the current in the case of the ignition system of current interruption type on the other, thus complicating and making bulky the general construction of the system. This problem becomes especially serious in the case of a cylinder-by-cylinder ignition system with a plurality of ignition coils corresponding to respective cylinders.